Method of preserving rubber



Patented Nov. 11, 1930 UNITED STATES PATENT OFFICE.-

J'AH TEPPEIA, OI AKRON, OHIO, ASSIGNOB TO THE GOODYEAR TIRE & RUBBER COI- rm, OF AKRON, OHIO, A. CORPORATION OF OHIO METHOD PRESENTING RUBBER R0 Drawing.

' My invention relates to the manufacture a of rubber products and it has particular reference to a method for improving the physical properties thereof. It is universally acknowledged that vulcanized caoutchouc compositions deteriorate More specifically, the invention contemplates the employment, in rubber composi-; tions, of the reaction products of naphthol with amines to serve as antioxidants.

The following specific compounds have been found to possess, to a marked degree, the properties of the general class, and they are illustrative of the principles of the invention. Ewample 1. Pheng l ,B-naphthylamina- This compound may be readily prepared by the reaction of B-naphthol with aniline.

011. NH, N'HCIHS B-naphthol Aniline Phenylfi naphthylamine.

One mol of fi-naphthoL'two mols of aniline, and one mol of fused calcium chloride 40 are heated at a temperature of 280 C. for nine hours under pressure. The crude product is steam distilled to remove the excess aniline and it is then treated with hot alkali and washed with water. The desired product crystallizes from alcohol upon cool- Application filed November 30, 1926. Serial No. 151,825.

in as colorless plates, having a melting point between 108 and 109 C.

The product was tested in stocks of the following composition; two percent of the antioxidant, based on the rubber content, being employed in both cases.

. Per cent Per cent Rubber 56.00 60.00 Zinc oxide 15.00 5.00 Gas black 23.00 25.00 Sulphur 1.60 1.80 Mineral rubber 3.20 5.00 Diphenylguanidine 1.20 Mercaptobenzothiazole 0.50 Stearic acid 2.70

The results of the ageing test are indicated in Table I:

Table I g No antioxidant 2% phenyl fl-naphthylamine After 12 days After 12 days After care at 50 C. 150# After cure at 50 C. 150! 'r. E. 'r. E. T. E. 'r. E.

T. is tensile strength in kgsJcmJ. E. is percent elongation.

In all cases the compounds were cured for thirty minutes at a temperature corresponding to 40'lbs. per square inch gaugesteam pressure.

Example 2. Phenyl a-mphthylamz'ne- This material may be prepared from alphanaphthol and aniline, using the same procedure as'that previously described. The product separates as practically colorless crystals having a melting point between 62 and 63 C. This material was tested in a stock having substantially the following composition, and the results are indicated in The test showed results set forth in the appended Table II. Table III.

PM Table III Rubber Iron oxlde 11165 Aite r6days Lime 1.00 riginal at50 2.1w Magnesium oxide 1.00 Cm Magnesmm carbonate 50.00 Tensile Elem Tensile Elan; Pine tar oil 2.50 strength gation strength gation Antioxidant 0.30

. No antioxidant... 155 855 Melteddown 50 min. at 40# Table II With antioxidant 150 850 160! 820 50 min. at 40# Original g gggg f mew From the foregoing examples, itwill be Cure 32 23: apparent that I have dlscovered a new class sile of materlals which may be utihzed to pre- Tenslle Elon Tensile Elon Strength strength satwn Strength gatwn serve rubber composltions from the deleterlous effects of the elements. Obvlously, other 2 2 5 95 compounds. than those mentioned could be No antioxidant. 30 71'6 2 1 d hth 1 d 120 73.1 268 49.5 o as emp oye oc-B- i-nap y amlne an ,8 6-

- di-naphthylamlne have similar properties, with phe 30 287 81 268 108 and other aromatic hydroxy derivatives may 1 79. 0 350 75. S 275 98 naphthylamme 20 be substituted for naphthol. In a l1ke man- Tensile strength in kgs/cmfl. Elongation in percent.

, Ewample 3. Diamz'no-dz'phenyl (Zi-fl-napkthyl methane-Two mols of beta-naphthol will react with formaldehyde in the presence of a condensing agent, such as sodium acetate, to form methylene di-B-naphthol, according to the following reaction. (Ber 39 :439)

OH HO Methylene di-fi-naphthol.

The reacting chemicals were mixed with calcium chloride and heated in a sealed tube for seven hours at a temperature of 280 C. The mixture was then subjected to steam distillation, leaving a semi-solid substance which was fractionally distilled in vacuo, the portion going over between 160 and 210 C. crystalizing from alcohol in the form of white needles having a melting point of about 105 C. Both the crude product and the pure material were tested and found to possess substantially equal antioxidant properties.

One part of antioxidant was added to a rubber composition containing the following ingredients Rubberacetone extracted 100.0 Zinc oxide 5.0 Sulphur 3.0 Hexamethylene tetramine 1.0 Stearic acid 1.5

ner, various amines may be used in place of aniline. In view of the nature of the invention, it is not intended that the scope thereof should be limited to the specific compounds enumerated above, but only such limitations should be imposed as are set forth in the following claims.

What I claim is:

1. A method of preserving rubber which comprises incorporating the reaction product of a naphthol and an aromatic amine in a vulcanizable mixture including rubber and vulcanizing the same, said reaction product being a non-accelerator.

2. A method of preserving rubber which comprises incorporating the reaction product of a naphthol and aniline in'a vulcanizable mixture including rubber and vulcanizing the same, said reaction product being a nonaccelerator.

3. A vulcanized rubber product vulcanized in the presence of the reaction product of a naphthol and aniline, said reaction product being a non-accelerator of vulcanization.

4;. The method of imparting age-resisting properties to rubber which comprises incorporating therewith phenyl-alpha-naphthylamine.

5. A vulcanized rubber composition having had incorporated therewith prior to vulcanization phenyl-alpha naphthylamine.

6. A method of treating rubber which comprises vulcanizing it in thepresence of a material having the following structural formula:

t R-N-Ri,

, in whichR represents a naphthyl group and canized in the, presence of a material having the following structural formula:

H B-IiT-Rn,

in which R represents a naphthyl group and R an aryl group, said material being substantially a non-accelerator of vulcanization.

8. A method of treating rubber which comprises vulcanizing it in the presence of a phenyl naphthyl amine, said amine being substantially a non-accelerator of vulcanization.

9. A rubber product that has been vulcanized in the presence of a phenyl naphthyl amine, which is a non-accelerator of vulcanization.

10. The process of producing an age-resisting rubber composition which comprises incorporating the reaction product of a primary aromatic amine with a naphthol into a rubber mix containing the usual vulcaniza-' tion ingredients and heating to the vulcanization temperature.

11. The process of producing an age-resisting rubber composition which comprises incorporating the reaction product of betanaphthol and an aromatic amine into a rubber mix containing the usual vulcanization ingredients and heating to the vulcanization temperature.

In witness whereof, I have hereunto signed my name.

JAN TEPPEMA. 

